Nuclear reactors, such as those described in "Nuclear Power Engineering," M. M. El-Wakil, McGraw-Hill Book Company, Inc., 1962, have been producing electricity by generating steam to drive turbines for many years. The steam is generated by heat from nuclear fuel rods arranged in vertical bundles in a reactor core.
The design of nuclear fuel rods has been improved significantly over the years. Scientists continue to research and develop new solutions to improve the operational reliability of the rods. To promote the continued improvement of fuel rods, it is desirable to study the fission gases generated within fuel rods during reactor operation. To study these gases, irradiated fuel rods are individually punctured in a subaqueous environment to release the fission gases for capture and examination.
Submerging the fuel rods protects the scientists from undue radiation exposure. A service pool adjacent the wet well and pressure vessel housing the reactor core is a convenient location to capture the fission gases.
A selected fuel rod is withdrawn from its bundle for penetration. Withdrawal may take place after the fuel bundle has been partially disassembled. U.S. patent application Ser. No. 177,097, filed Aug. 11, 1980, shows one way to disassemble a fuel bundle. After withdrawal from the bundle, penetration, and capture of fission gas, this selected fuel rod is stored underwater for an indefinite period of time. A certain amount of fission gas inevitably leaks through the punctured hole. This gas is radioactive, and even though only trace amounts are released into the fuel storage pool, concern has been expressed regarding the wisdom of permitting fission gases unconstrained access to the service pool.
It is accordingly an object of the instant invention to contain fission gases leaking through a puncture hole in a nuclear fuel rod.
Another object of the instant invention is remotely and sealingly to crimp a malleable sleeve over the puncture hole through which fission gases escape from underwater nuclear fuel rods.